Getting a Mac is always a good idea.
We made the switch last year and I'm very happy with everything, especially the UNIX command-line (but then again I guess I'm a geek). On the other hand there isn't much I can do with the Mac I couldn't also do with Windows (ok, most things are easier/smoother on the Mac).
Anyway, what brand are your cards and card reader? It may be a brand thing. For instance I've noticed that some of the non top brands (top being Sandisk, Lexar, ...) do not always work properly with all card readers.
Cheers